dlath Please I was using CT before and now using shunt resistor, I have configured the ADE7953 EVAL board as directed in the UG-194. I used shunt resistor of 200microOhms. on the board there is no way to bypass the 51ohms burden resistor, so I removed it. I used the filter circuit of 1K resistor with 0.033microFarads capacitor. pls kindly attend to the challenges I'm facing using shunt, I look forward to reading from you.
Here are my configuration values and error readings.
- default reading ( without calibration) are:
error reading at
- 50A is 3.9909 at p.f of 1, and 9..0542 at p.f of 0.5L
- 5A is 1.6528 at p.f of 1, and 2.6420 at p.f of 0.5L
- 0.05A is -4.6647 at p.f of 1
- reading ( after AWGAIN calibration) are
error reading at
- 50A is 0.9670 at p.f of 1, and 0.5543 at p.f of 0.5L
- 5A is -0.0284 at p.f of 1, and -1.6135 at p.f of 0.5L
- 2.5A is -0.7582 at p.f of 1, and -3.1289 at p.f of 0.5L
- 0.5A is -7.0258 at p.f of 1, and -16.128 at p.f of 0.5L
reading ( after PHACAL and AWGAIN calibration) it gives correct accuracy at 5A, p.f of 1 and 0.5L.
- After offset,PHACAL,AWGAIN calibration, the reading at 5A is 1.018. at p.f of 1 and 1.6584 at p.f of 0.5L
my question goes does;
- what am i doing wrong ?
- how do i solve this problem?
- i discovered that after some time the reading goes higher again, does temperature affects the accuracy of the metering IC?
- culled from the AN118 "Do not perform offset calibration with grounded inputs because a low level signal is necessary to accurately measure the offset." explain this pls? because i am using shunt and its single ended. from the configuration, the phase is connected to ground.